U.S. patent number 6,915,962 [Application Number 10/443,114] was granted by the patent office on 2005-07-12 for apparatus for providing aerosol for medical treatment and methods.
This patent grant is currently assigned to Aerogen, Inc.. Invention is credited to John Power, Des Regan, Niall Smith.
United States Patent |
6,915,962 |
Power , et al. |
July 12, 2005 |
Apparatus for providing aerosol for medical treatment and
methods
Abstract
Embodiments of the present invention include apparatus and
methods for aerosolizing liquid. One embodiment of the invention
provides an apparatus for generating an aerosol. The apparatus
includes an actuator having a first face and a second face and
defining an opening therethrough, as well as a vibratory element in
mechanical communication with the actuator, and a sealing member
configured to isolate the vibratory element from a surrounding
environment. In accordance with certain embodiments, the apparatus
further comprises an aerosolization element mounted on the actuator
and disposed substantially over the opening, wherein the
aerosolization element defines at least one aperture therethrough.
Hence, the vibratory element may be operated to vibrate to cause
movement of the aerosolization element in such a manner that a
liquid at the first face of the aerosolization element can be
dispensed as an aerosol through the at least one aperture. Some
embodiments feature an electrode coupled to the vibratory
element.
Inventors: |
Power; John (Galway,
IE), Regan; Des (Galway, IE), Smith;
Niall (Galway, IE) |
Assignee: |
Aerogen, Inc. (Mountain View,
CA)
|
Family
ID: |
29550178 |
Appl.
No.: |
10/443,114 |
Filed: |
May 20, 2003 |
Current U.S.
Class: |
239/102.2;
552/596; 552/601 |
Current CPC
Class: |
A61M
11/005 (20130101); A61M 15/0085 (20130101); B05B
17/0646 (20130101) |
Current International
Class: |
B05B
17/04 (20060101); B05B 1/02 (20060101); B05B
1/08 (20060101); B05B 001/08 () |
Field of
Search: |
;239/4,102.1,102.2,552,596,601,DIG.19 ;128/200.14,200.16
;264/259,328.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Ganey; Steven J.
Attorney, Agent or Firm: Townsend and Townsend and Crew
LLP
Parent Case Text
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a nonprovisional of provisional U.S. Patent
App. Ser. No. 60/382,256, entitled "APPARATUS AND METHODS OF
PROVIDING AEROSOL FOR MEDICAL TREATMENT," filed May 20, 2002 by
Power et al., the entire disclosure of which is incorporated herein
by reference for all purposes.
Claims
What is claimed is:
1. An apparatus for generating an aerosol, comprising: an actuator
having a first face and a second face and defining an opening
therethrough; an aerosolization element mounted on the actuator and
disposed substantially over the opening, wherein the aerosolization
element defines at least one aperture therethrough; a vibratory
element in mechanical communication with the actuator; and a
sealing member configured to isolate the vibratory element from a
surrounding environment; wherein the vibratory element may be
operated to vibrate to cause movement of the aerosolization element
in such a manner that a liquid at a first face of the
aerosolization element can be dispensed as an aerosol through the
at least one aperture; and wherein the sealing member comprises an
elastomer.
2. The apparatus of claim 1, wherein the vibratory element is
annular.
3. The apparatus of claim 1, wherein the vibratory element
comprises a piezoelectric ceramic.
4. The apparatus of claim 1, wherein the sealing member is annular,
covering at least a portion of the first face of the actuator, at
least a portion of the second face of the actuator, and at least a
portion of the vibratory element.
5. The apparatus of claim 1, wherein the elastomer comprises a
rubber.
6. The apparatus of claim 5, wherein the rubber is a synthetic
rubber.
7. The apparatus of claim 5, wherein the rubber is silicone.
8. The apparatus of claim 1, wherein the sealing member is molded
around at least a portion of the vibratory element.
9. The apparatus of claim 8, wherein the sealing member is formed
by injection-molding.
10. The apparatus of claim 1, further comprising at least one
electrode coupled to the vibratory element.
11. The apparatus of claim 1, further comprising at least one layer
of bonding material between the sealing member and the vibratory
element.
12. The apparatus of claim 11, wherein the bonding material couples
the sealing member relatively securely to at least one of the
vibratory element and the actuator.
13. The apparatus of claim 11, further comprising at least one
electrode coupled to the vibratory element, wherein the bonding
material provides a relatively impervious barrier between the
electrode and the surrounding environment.
14. The apparatus of claim 11, wherein the bonding material is
relatively impervious to a relatively severe environmental
condition.
15. The apparatus of claim 14, wherein the relatively severe
environmental condition is selected from a group consisting of
heat, humidity, pressure, alternating cycles of vacuum and
pressure, and a corrosive chemical.
16. The apparatus of claim 11, wherein the bonding material is
selected from the group consisting of a paint, an epoxy, an
adhesive and a primer.
17. The apparatus of claim 11, wherein the at least one layer of
bonding material comprises a first application of a first bonding
material and a second application of a second bonding material.
18. The apparatus of claim 17, wherein the first and second bonding
materials are the same bonding material.
19. The apparatus of claim 11, wherein the at least one layer of
bonding material is applied room temperature and cured at a
relatively high temperature for a specified period of time.
20. The apparatus of claim 19, wherein the relatively high
temperature is above about 100 degrees C.
21. The apparatus of claim 20, wherein the relatively high
temperature is between about 100 degrees C. and about 150 degrees
C.
22. The apparatus of claim 21, wherein the relatively high
temperature is between about 120 degrees C. and about 140 degrees
C.
23. The apparatus of claim 22, wherein the relatively high
temperature is about 130 degrees C.
24. The apparatus of claim 19, wherein the specified period of time
is between about 15 minutes and about 45 minutes.
25. The apparatus of claim 24, wherein the specified period of time
is about 30 minutes.
26. The apparatus of claim 11, wherein the bonding material further
comprises an adhesive situated between the vibratory element and
the actuator.
27. The apparatus of claim 26, wherein the vibratory element
comprises an inner surface and an outer surface, and wherein the
adhesive is further situated between the sealing member and at
least a portion of at least one of the inner and outer surfaces of
the vibratory element.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to the field of pulmonary drug
delivery, and in particular to the aerosolizing of liquid
medicament into fine liquid droplets for inhalation.
In the fields of drug delivery and pulmonary therapy, the
aerosolization of drugs and other medicaments for pulmonary
delivery can provide significant therapeutic benefits. To realize
those benefits, there have arisen a variety of atomizers and
nebulizers, which can vary significantly in methods of operation.
For instance, some aerosol generators operate by vibrating at a
relatively high frequency an aperture plate in contact with the
material to be aerosolized. By way of example, U.S. Pat. Nos.
5,164,740; 5,586,550; 5,758,637; and 6,235,177, the complete
disclosures of which are herein incorporated by reference for all
purposes, describe exemplary devices for producing fine liquid
droplets in such a fashion. Such devices have proven to be
tremendously successful in aerosolizing liquids. Another technique
for aerosolizing liquids is described in U.S. Pat. No. 5,261,601,
also incorporated herein by reference for all purposes, and
utilizes a perforate membrane disposed over a chamber. The
perforate membrane comprises an electroformed metal sheet using a
"photographic process" that produces apertures with a cylindrical
exit opening.
Commonly, such aerosol generators-operate by using a vibratory
element to drive an aerosolizing element (e.g., aperture plate,
membrane, etc.). In many cases, the vibratory element comprises a
piezoelectric and/or piezomagnetic material such as one of many
ceramics known in the art to exhibit such properties. When excited
by the appropriate field, the piezo will expand/contract, such that
application of an oscillating field can produce oscillating
vibration of the piezo (and, by extension, the aerosolizing
element) at a frequency related to that of the oscillating field.
Often, the field will be applied to the piezo through one or more
electrodes in electrical communication with the piezo.
In use, aerosol generators can be subjected to a variety of
environmental conditions, many of which can threaten to degrade the
performance of the generator; for instance, during operation, the
piezo and/or the electrodes may be in danger of exposure to the
fluid being aerosolized. Those skilled in the art will recognize
that, in many cases, prolonged exposure to such fluids can result
in corrosion of the piezo and/or the electrodes, and even
relatively brief exposure can vitiate the electrical communication
between the piezo and the circuitry by which it is driven (for
example, by short-circuiting the electrodes and/or otherwise
interfering with the electrical communication between the
electrodes and the piezo).
Likewise, various cleaning procedures can prove harmful to the
operation of the aerosol generator if care is not taken. For
instance, in many cases aerosol generators are used in hospitals
and/or other institutional settings, where strict sanitization
policies often are enforced to prevent cross-infection by multiple
users of a generator. Merely by way of example, aerosol generators
may be exposed to potentially corrosive substances, such as
solvents and disinfectants. In addition, generators may be exposed
to relatively high levels of heat, pressure, and/or humidity during
sanitization processes, such as autoclaving and the like. Without
protection, therefore, the relatively sensitive components of
aerosol generators (including, for example, their piezos and/or
electrodes) may be damaged during sanitization and/or the
operational lives of such components may be limited significantly
by repeated sanitization procedures.
BRIEF SUMMARY OF THE INVENTION
Embodiments of the invention, therefore, address certain
limitations in the prior art and include apparatus and methods for
aerosolizing liquid. For instance, one embodiment of the invention
provides an apparatus for generating an aerosol. The apparatus
includes an actuator having a first face and a second face and
defining an opening therethrough, as well as a vibratory element in
mechanical communication with the actuator, and a sealing member
configured to isolate the vibratory element from a surrounding
environment. In accordance with certain embodiments, the apparatus
further comprises an aerosolization element mounted on the actuator
and disposed substantially over the opening, wherein the
aerosolization element defines at least one aperture therethrough.
Hence, the vibratory element may be operated to vibrate to cause
movement of the aerosolization element in such a manner that a
liquid at the first face of the aerosolization element can be
dispensed as an aerosol through the at least one aperture. Some
embodiments feature an electrode coupled to the vibratory
element.
In accordance with certain embodiments, the vibratory element is
annular in shape and/or comprises a piezoelectric ceramic In other
embodiments, the sealing element is annular, such that it covers at
least a portion of the first face of the actuator, at least a
portion of the second face of the actuator, and at least a portion
of the vibratory element. In further embodiments, the sealing
element can comprise an elastomer and/or a rubber, which can be,
merely by way of example, a synthetic rubber or a silicone. The
sealing member can be molded around at least a portion of the
vibratory element, and can be formed by injection molding.
Some embodiments include one or more layers of bonding material
between the sealing element and the vibratory element. The bonding
material can couple the sealing member relatively securely to at
least one of the vibratory element and the actuator and can, in
some cases, provide a relatively impervious barrier between the
electrode and the surrounding environment. The bonding material can
be relatively impervious to a relatively severe environmental
condition, which can include, inter alia, heat, humidity, pressure,
alternating cycles of vacuum and pressure, and a corrosive
chemical.
In other embodiments, the bonding material can be selected from the
group consisting of a paint, an epoxy, an adhesive and a primer,
and the at least one layer of bonding material can comprise a first
application of a first bonding material and a second application of
a second bonding material. The first and second bonding materials
can be the same bonding material. In further embodiments, the
bonding material comprises an adhesive situated between the
vibratory element and the actuator. In some cases, the vibratory
element comprises an inner surface and an outer surface, and the
adhesive can be situated between the sealing element and at least a
portion of at least one of the inner and outer surfaces of the
vibratory element.
Other embodiments of the invention provide methods of making and/or
using aerosol generator assemblies. One exemplary method for making
an aerosol generator assembly comprises providing an aerosol
generator, which can be similar to one of the aerosol generators
discussed above. The method also includes providing a mold assembly
formed to receive the aerosol generator, placing a mold material
into the mold assembly, allowing mold material to form a sealing
element about at least a portion of the aerosol generator and
removing the aerosol generator from the mold assembly.
In some cases, placing the mold material into the mold assembly
comprises injection molding the mold material. In other cases, the
method includes preparing at least one of the vibratory element and
the actuator. Preparing the vibratory element and/or actuator can
comprise chemical etching of those components.
In certain embodiments, the method further comprises applying at
least one layer of bonding material between the mold material and
least one of the vibratory element and the actuator. Applying at
least one layer can include applying a layer of a first bonding
material and applying a layer of a second bonding material. The
first bonding material and the second bonding material can be the
same bonding materials. One or more layers can be applied at room
temperature and cured at a relatively high temperature for a
specified period of time. The relatively high temperature is above
about 100 degrees C., more specifically between about 100 degrees
C. and about 150 degrees C. In some cases, the relatively high
temperature is between about 120 degrees C. and about 140 degrees
C., and more specifically, about 130 degrees C. In other cases, the
specified period of time is between about 15 minutes and about 45
minutes.
BRIEF DESCRIPTION OF THE DRAWINGS
A further understanding of the nature and advantages of the present
invention may be realized by reference to the figures which are
described in remaining portions of the specification. In the
figures, like reference numerals are used throughout several to
refer to similar components. In some instances, a sub-label
consisting of a lower case letter is associated with a reference
numeral to denote one of multiple similar components. When
reference is made to a reference numeral without specification to
an existing sub-label, it is intended to refer to all such multiple
similar components.
FIG. 1 is a plan view of an aerosol generator assembly, in
accordance with various embodiments of the present invention.
FIG. 2 a side cross-sectional view of an aerosol generator
assembly, in accordance with various embodiments of the present
invention.
FIG. 3 is a bottom view of an aerosol generator assembly, in
accordance with various embodiments of the present invention.
FIG. 4 is a side view of an aerosol generator assembly, in
accordance with various embodiments of the present invention.
FIG. 5 is a top perspective view of an aerosol generator assembly,
in accordance with various embodiments of the present
invention.
FIG. 6 is a bottom perspective view of an aerosol generator
assembly, in accordance with various embodiments of the present
invention.
FIG. 7 illustrates an aerosol generator assembly in accordance with
various embodiments of the invention.
FIGS. 8A and 8B illustrate a portion of an aerosol generator
assembly with a plurality of layers of bonding materials, in
accordance with various embodiments of the invention.
FIGS. 9A and 9B illustrate a portion of an aerosol generator
assembly having an adhesive situated between an actuator and a
vibratory element, in accordance with various embodiments of the
invention.
FIG. 10 illustrates a cross section of an aerosol generator
assembly having a single layer of bonding material applied to
portions of a vibratory element, in accordance with various
embodiments of the invention.
FIG. 11 illustrates a cross section of an aerosol generator
assembly having a single layer of bonding material applied to
portions of a vibratory element, an actuator and an aerosolization
element, in accordance with various embodiments of the
invention.
FIG. 12 illustrates a cross section of an aerosol generator
assembly having a first layer of bonding material applied to
portions of a vibratory element and a second layer of bonding
material applied to portions of the vibratory element, an actuator
and an aerosolizing element, in accordance with various embodiments
of the invention.
FIG. 13 illustrates a cross section of an aerosol generator
assembly having an adhesive disposed between a vibratory element
and an actuator, in accordance with various embodiments of the
invention.
FIG. 14 illustrates a cross section of an aerosol generator
assembly having an adhesive disposed between a vibratory element
and an actuator, a first layer of bonding material applied to
portions of the vibratory element, and a second layer of bonding
material applied to portions of the vibratory element, the
actuator, and an aerosolizing element, in accordance with various
embodiments of the invention.
FIG. 15 illustrates a cross section of an aerosol generator
assembly having an adhesive disposed between a vibratory element
and an actuator and first layer of bonding material applied to
portions of the vibratory element, in accordance with various
embodiments of the invention.
FIG. 16 illustrates a cross section of an aerosol generator
assembly having an adhesive disposed between a vibratory element
and an actuator and first layer of bonding material applied to
portions of the vibratory element, the actuator, and an
aerosolization element, in accordance with various embodiments of
the invention.
FIG. 17 illustrates a cross section of an aerosol generator
disposed within a mold assembly, in accordance with embodiments of
the invention.
FIG. 18 illustrates a detail view of the aerosol generator and mold
assembly of FIG. 17.
FIG. 19 illustrates a process flow diagram for producing an aerosol
generator assembly in accordance with various embodiments of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention include apparatus and methods
for aerosolizing liquid. In accordance with one embodiment, an
aerosol generator assembly is provided, comprising an aerosol
generator and a sealing element overmolded onto the aerosol
generator. Those skilled in the art will appreciate that, in
accordance with certain embodiments of the invention, an aerosol
generator comprises a piezoelectric and/or piezomagnetic vibratory
element (a "piezo") for vibrating an aerosolization element to
aerosolize a fluid. In many cases, the piezoelectric member is
driven by application of an electric and/or magnetic field, which
often is supplied through an electric circuitry coupled to the
piezo by one or more electrodes. The connection between the
circuitry and the electrodes can be of any type that is operative
to supply electric current to the piezo, including, for instance,
conductive metal wires (optionally, with non-conductive
insulation), conductive polymeric materials, and the like.
In accordance with some embodiments of the invention, a sealing
member, which can comprise a variety of relatively impermeable
and/or elastic substances (including, merely by way of example,
elastomers, rubbers (both natural and synthetic), urethanes,
silicon and the like) and can serve to isolate/protect the piezo
and/or electrodes from the surrounding environment, which can
sometimes include relatively severe environmental conditions,
including without limitation, the conditions described below, such
as relatively high heat, pressure, and atmospheric moisture,
immersion in fluids, exposure to corrosive fluids, and the
like.
Merely by way of example, a sealing member in accordance with some
embodiments comprises a thermoplastic elsastomer known in the art
as Santoprene.TM., which is commercially available from Advanced
Elastomer Systems, L.P., of Akron, Ohio, USA. As described below,
the sealing member can be formed by a variety of techniques,
including for example, injection molding. U.S. Pat. No. 6,554,201,
the entire disclosure of which is incorporated herein by reference
for all purposes, describes one exemplary injection molding process
that can be used in conjunction with aerosol generators.
In other embodiments, the sealing member can be used as a mounting
apparatus for coupling the aerosol generator to a housing. Those
skilled in the art will recognize that aerosol generators often are
mounted within a housing for operation, such that the housing can
provide (and/or be in communication with) a supply of fluid to be
aerosolized, such as a chamber and/or the like. Additionally, the
housing can also be an integrated part of a nebulizer system, such
that it provides fluid communication between the aerosol generator
and a patient's airway, either passively (such as, for instance, in
an inhaler, where the patient inhales the aerosolized fluid from
the housing) and/or actively (such as, for instance, when the
housing is part of a respirator system). In some embodiments,
therefore, the sealing member, which, as noted, can comprise a
relatively elastic and/or flexible substance, can couple the
aerosol generator to the housing securely enough to prevent
dislodging of the generator, yet flexibly enough that the vibratory
characteristics of the generator are not significantly impacted,
thereby substantially maintaining the performance of the aerosol
generator.
In still other embodiments, one or more bonding materials can be
applied between and/or among the sealing member and various
components of the aerosol generator. In some cases, bonding
materials can include adhesives, epoxies, paints, primers and the
like. Those skilled in the art will recognize that certain bonding
materials can provide a relatively secure coupling between the
aerosol generator and the overmold. Further, the bonding materials
can be selected based on their abilities to enhance the vibratory
performance of the generator and/or create or reinforce a barrier
between the piezo (and/or its electrodes) and the surrounding
environment. In many cases, the bonding materials are relatively
impervious to environmental conditions to which aerosol generators
commonly are exposed during operation, sanitization, etc. For
instance, as discussed below, certain bonding materials can be
relatively immune to an autoclave environment, which can introduce
significantly elevated heat and pressure, along with relatively
high levels of atmospheric water vapor and/or other fluids.
Likewise, certain bonding materials can be impervious to any
corrosive effects of cleaning fluids and/or fluids to be
aerosolized.
Turning now to FIG. 1, a top view of an aerosol generator assembly
100, including a sealing member 104, is illustrated, in accordance
with certain embodiments of the invention. The aerosol generator
assembly 100 further includes an aerosolization element 108, an
actuator 112, and one or more electrical conduits 116. As
illustrated by FIG. 2, a cross-sectional diagram of the assembly
100, an aerosol generator can further include a piezoelectric
member 120, as well as a bottom plate 124. Although not apparent in
the cross-sectional illustration of FIG. 2, those skilled in the
art will appreciate from the view of FIG. 1 that the actuator 112
can be annular in shape, thereby describing a central aperture,
with the aerosolization element 108 bonded to the inner portion of
the annular actuator 112 and spanning the central aperture.
Likewise, the piezo 120 can be annular in shape and can be bonded
to a central and/or outer portion of the actuator 112.
Also as illustrated by FIG. 2, the sealing member 104 can be formed
in such a fashion as substantially to surround the piezo 120 and
actuator 112, and can, as illustrated in FIG. 1, be cup-shaped
and/or annular in shape as well. Thus, in some embodiments, the
sealing member 104 can be formed to have a relatively thick
exterior portion that tapers to a relatively narrow interior
portion, which can allow for more secure mounting in a housing
without impacting the ability of aerosolized liquid to disperse
away from the aerosolization element 108. To further facilitate
mounting, the sealing member 104 can include one or more features
(which may be integrally formed with the sealing member 104) to
allow efficient coupling of the assembly 100 with the housing.
Merely by way of example, the sealing member 104 of FIG. 2 includes
a notch 128, which can be used for this purpose, in its exterior
circumference.
FIG. 3 illustrates a bottom view of the aerosol generator assembly
100. As illustrated by FIG. 3, in accordance with certain
embodiments, the sealing member 104 can extend around the outer
surface of the generator to encompass a portion of the bottom face
of the aerosol generator. In some cases, a portion of bottom face
of the actuator 112 may be left exposed, while in other cases, the
sealing member 104 may extend inward across the bottom of the
generator toward the actuator's central aperture, leaving only the
aperture plate 108 exposed. Also as shown on FIG. 3, the sealing
member 104 may be formed to allow insertion of one or more
electrical conduits 116 (e.g., insulated wires, etc.) through the
sealing member 104 for coupling to a piezo, one or more electrodes,
etc. In alternative embodiments, the electrical conduits 116 can be
attached to the aerosol generator before formation of the sealing
member 104, such that the sealing member 104 is molded around the
conduits 132.
FIG. 4 illustrates a side view of the aerosol generator assembly
100, displaying the circumferential notch 128 described above, as
well as the electrical conduits 132. FIGS. 5 and 6 illustrate
perspective drawings of the assembly 100, as seen from the top and
bottom, respectively.
FIG. 7 provides a cross-sectional illustration of an aerosol
generator assembly 700 in accordance with other embodiments of the
invention. The aerosol generator assembly 700 includes a sealing
member 704 formed around an actuator 708 and a vibratory element
712 in mechanical communication with one another. The assembly 700
further includes an aerosolization element 716 mounted on the
actuator 708 in a fashion similar to that described above. The
sealing member 704 is generally annular in shape.
FIG. 8A illustrates a cross-sectional view of an aerosol generator
assembly 800 in accordance with some embodiments of the invention.
The assembly 800 features a sealing member 804 molded around an
aerosol generator, which includes an actuator 808 in mechanical
communication with a piezoelectric vibratory element 812. An
aerosolization element 816 can be mounted on the actuator 808 and
can be used to aerosolize a liquid in a manner similar to that
discussed above. The actuator has a first face 820 and a second
face 824. The actuator 808 can be annular, having an outer surface
828 and an inner surface 832, which can define a central aperture
through the actuator 808. In some cases, the outer surface 828 can
define a flange. The aerosolization element 816 can be mounted so
as to cover substantially the central aperture, and the
aerosolization element 816 itself can have one or more apertures
through which the aerosolized material can flow.
The vibratory element 812 can be in mechanical communication with
the actuator 808. For instance, the vibratory element 812 can be
mechanically coupled to the actuator 808 through a variety of
means. Merely by way of example, the vibratory element 812 can be
bonded to the actuator 808 with an adhesive 836. For instance, in
some cases, the vibratory element 812 may be attached with
mechanical fasteners to the actuator 808. In other cases, the
vibratory element 812 and the actuator 808 may be integrally
formed, perhaps from the same material. In certain embodiments, as
shown in FIG. 8A, the vibratory element 812 may be configured in a
ring of rectangular cross-section, having an outer surface 840 and
an inner surface 844, and the adhesive can be placed adjacent to
either surface 840, 844, or both, to provide mechanical coupling
between the vibratory element 812 and the actuator 808. The
vibratory element can also have a first face 852 and a second face
856, and one or more electrodes 860 may be mounted on either face
852, 856, or both. In some cases, a bonding material (for instance,
an adhesive) may be placed between the first face 852 and the
actuator 808 and/or adjacent to the second face (either between the
second face 856 and the electrodes 860 or over the second face and
the electrodes 860, or both.
In some cases, one or more layers of bonding material may be
disposed between and/or among the sealing member 804 and various
components of the aerosol generator. As discussed above, one such
bonding material may be an adhesive 844. Other bonding materials
can include paints, epoxies, primers, and the like, as discussed
herein. As illustrated by FIG. 8A, a first layer of bonding
material 864 can be applied over the second face 856 of the
vibratory element 812 and/or the electrode 860. The first layer 864
additionally can be disposed over any adhesive 836 adjacent to the
outer 840 and/or inner 844 surfaces of the vibratory element. In
some cases, as shown in FIGS. 8A and 8B, the adhesive 836 can be
tapered, such that the first layer 864 can be applied to the point
where the adhesive tapers to be flush with the actuator 808,
forming a barrier over the vibratory element 812, the electrode
860, and any adhesive 836. Depending on the embodiment, any of the
bonding materials used herein can be applied as the first layer
864. In a particular embodiment, the first layer 864 can be a paint
and/or an epoxy.
Other embodiments can include one or more additional layers 868 of
bonding material, which also can comprise any of the bonding
materials discussed herein. The additional layers 868 can overlay
the first layer 864 and can, additionally, be applied to portions
of the actuator 808. As illustrated more clearly by FIG. 8B, in
some cases, the first layer 864 can be applied flush with (or
slightly overlapping) the aerosolizing element 816, such that the
additional layers 868 can be applied over the first layer and a
portion of the aerosolizing element 816. If desired, the additional
layers 868 can also be applied around the outer surface 828 of the
actuator and can cover at least a portion of the bottom face 824 of
the actuator.
In some embodiments, the sealing member 804 can comprise an
elastomer, including any of those discussed above. In a particular
embodiment, the sealing member 804 may comprise silicone. A
silicone that may be used in accordance with the present invention
is a two part silicone, available from a company known as
Wacker-Chemie GmbH, Geschaftsbereich Silicone, Hanns-Seidel-Platz
4, D-81737 Muchen (Munich, Germany). Such silicone is known to be
described in a product description captioned "Elastosil .RTM. LR
3003/10 A, B-LR 3003/80 A, B." One variety of such silicone that
may be used in accordance with the present invention is designated
as 40 Shore, representative of relative hardness of the cured
silicone.
As noted above, in some embodiments, prior to molding the sealing
member 804 about the aerosol generator, a layer of primer (which
can be thought of as one of the layers 868 in FIG. 8A) may be
applied to surfaces of the aerosol generator receiving the
overmold, which can include the vibratory element, the electrode,
the portions of the actuator, and a portion of the aerosolization
element, such as the flange, or part of the flange. The primer may
be applied to cover a slightly larger area than the overmold, to
ensure that there is sufficient coverage of the primer to maximize
bonding of the overmold. A primer that may be used in accordance
with the present invention is known as CF6-135 High Technology
Silicon Primer (Clear) available from a company known as NuSil
Technology, Carpenteria, Calif., USA.
In other embodiments, a layer of epoxy (which can be thought of as
the first layer 864 in FIG. 8A) may be applied to the exposed
surfaces of the vibratory element. This layer can be applied prior
to the application of a primer, or may be applied without the
addition of a primer. The painted epoxy may comprise an
autoclavable epoxy, such as, for example, a product designated as
Masterbond EP3HTMED by a company known as Masterbond of New York,
USA. The epoxy paint may be applied in a first layer and a second
layer. In such case, it may be applied at room temperature with a
fine point paintbrush. It may be cured at 130 degrees C. for 30
minutes, whereupon a second application may be applied at room
temperature, and likewise cured at 130 degrees C. for 30
minutes.
It will be appreciated that the thickness of any bonding material
(whether paint, primer, epoxy or the like) can be relatively small
compared to the size of the aerosol generator and sealing member.
As such, each bonding material may range from approximately a
nanometer to approximately several micrometers in thickness,
depending on the material used. Accordingly, in the various figures
accompanying this application, the paint and primer thickness are
enlarged for purposes of illustration.
FIGS. 9A and 9B illustrate how an adhesive may be used in
accordance with some embodiments of the invention. An aerosol
generator assembly 900 may be formed of a sealing member 904 molded
around an aerosol generator, which can comprise a vibratory element
908, an actuator 912 and an aerosolizing element 916. A relatively
thin layer of adhesive 920, which can be an epoxy adhesive, can be
disposed between the vibratory element 908 and the actuator 912.
Excess adhesive may adhere to the sides of the vibratory element
908, and, in this way, can be used to provide a more secure fit
between the sealing member 904 and the aerosol generator. Some
embodiments, therefore, omit any additional bonding materials, as
the adhesive 920 and sealing member act to provide a relatively
impervious barrier between the surrounding environment and the
vibratory element 908 (and, optionally, one or more electrodes,
which are not shown in FIGS. 9A and 9B).
FIGS. 10-16 illustrate several different embodiments of the
invention, employing a variety of bonding materials between and
among the sealing member and various components of the aerosol
generator. For ease of illustration, each of FIGS. 10-16 omit the
electrodes, but those skilled in the art will appreciate, based on
the disclosure herein, that electrodes could be incorporated as
desired into each of the illustrated embodiments. Turning now to
FIG. 10, an aerosol generator assembly 1000 is illustrated. The
assembly includes a single layer 1004 of bonding material, which
can be primer, paint, epoxy, etc., applied to the top face and each
side face of a vibratory element 1008, which is mounted on an
actuator 1012. Hence, the bonding material 1004, in conjunction
with the actuator 1012, completely surrounds the vibratory element.
In the assembly 1100 of FIG. 11, a layer of bonding material 1104
has been applied not only to surround the upper, inner and outer
surfaces of the vibratory element 1008, but also has been applied
to portions of the actuator 1012 (including the flange and bottom
surface thereof), as well as to portions of the aerosolizing
element 1016. Thus, the bonding material 1104 has been applied to
every surface of the aerosol generator with which the sealing
member 1020 comes into contact.
FIG. 12 illustrates an aerosol generator assembly 1200 employing a
first layer 1204 and a second layer 1208 of bonding material. The
first layer 1204 has been applied to the top, inner and outer
surfaces of the vibratory element 1008, similar to layer 1004 in
FIG. 10. The second layer 1208 is applied over the top of the first
layer 1204 and also to portions of the actuator 1216 (including,
again, portions of the flange and bottom surfaces of the actuator),
as well as to the outer portion of the aerosolizing element 1016.
Hence, like the layer 1104 in FIG. 11, the second layer 1208 has
been applied to every surface of the aerosol generator with which
the sealing member 1020 comes into contact.
FIG. 13 illustrates an embodiment of an aerosol generator assembly
1300 similar to that discussed with respect to FIGS. 9A and 9B, in
which the bonding material 1304 (perhaps an adhesive) is applied
between the vibratory element 1008 and the actuator 1012. In
contrast, the assembly 1400 of FIG. 14 includes the adhesive 1304
between the vibratory element 1008 and the actuator 1012, as well
as additional layers 1404 and 1408, which can be thought of as
similar to layers 1204, 1208 respectively, illustrated in FIG. 12.
FIG. 15 illustrates an aerosol generator assembly 1500 in which a
layer of adhesive 1504 is disposed between the vibratory element
1008 and the actuator 1012. Further, a layer 1516 of bonding
material overlays the adhesive 1504 and the vibratory element 1008,
such that the adhesive 1504 and the layer 1516 of bonding material
together function to completely encapsulate the vibratory element
1008. The assembly 1600 of FIG. 16 is similar to the assembly 1500
of FIG. 15, except that the layer of bonding material 1604 is
applied not only to the adhesive 1504 and the vibratory element
1008, but also to portions of the actuator 1012 and aerosolizing
plate 1016, effectively coating each surface that will be in
contact with the sealing member 1020.
Turning now to the molding process, FIG. 17 illustrates an
exemplary mold assembly 1700 for molding a sealing member onto an
aerosol generator, in accordance with embodiments of the invention.
The mold assembly 1700 is designed to accept an aerosol generator
1704 and defines a cavity 1708 into which mold material may be
placed. The cavity defines the shape of the sealing member to be
molded. In various embodiments, the mold material may comprise any
of the materials discussed above with regards to the composition of
a sealing member. In a particular embodiment, the mold material is
capable of being injection molded. In other cases, the mold
material can be in a liquid or semi-liquid form. The mold material
can be placed into the cavity 1708 through any suitable method
known in the art, including merely by way of example, injection
molding via channel 1712. Those skilled in the art will appreciate
that the mold assembly 1700 can comprise multiple components
1716a-d, which can be disassembled after the sealing member has
hardened and/or cured, to allow for easy removal of the finished
article. FIG. 18 illustrates a detail drawing of the mold assembly
1700 after mold material 1800 has been injected into the
cavity.
Hence, certain embodiments of the invention provide methods for
creating aerosol generator assemblies. One exemplary embodiment
1900 is illustrated by FIG. 19. It should be noted that, while the
procedures in method 1900 are illustrated and discussed in a
certain order for ease of description, embodiments of the invention
are not limited to any particular order.
The method 1900 comprises providing a aerosol generator (block
1904), which can, in some embodiments, include any of the aerosol
generators discussed herein. At block 1908, the aerosol generator
can be prepared to receive a bonding material and or to be molded
with a sealing member. Preparation can include, inter alia,
priming, scoring, chemical etching, and the like. At block 1912, a
layer of bonding material, such as adhesive, epoxy, paint, primer
and/or the like can be applied, and at block 1916 that layer can be
cured. In some cases, the application of the bonding material can
be done by dipping, paintbrush, airbrush, and/or other known
application techniques. In other cases, the curing process can take
place at a relatively high temperature, for a specified period of
time. Optionally, the application (block 1912) and/or curing (block
1916) procedures can be repeated as necessary to produce multiple
layers of bonding material and/or a single, thicker layer of
material.
At block 1920, the aerosol generator can be placed within a mold
assembly, and at block 1924, mold material may be placed into one
or more appropriate cavities in the mold assembly. As noted above,
block 1924 can include any appropriate procedure, including
injection molding, packing, and the like. The mold material can
then be allowed to form (e.g., cure, harden, etc.) to produce a
sealing member molded onto the aerosol generator (block 1928), at
which point the finished aerosol generator assembly can be removed
from the mold assembly (block 1932).
While the above is a detailed description of illustrative
embodiments of the invention claimed herein, various alternatives,
modifications, and equivalents may be employed without departing
from the present invention. Thus, although the foregoing has been
described in detail for purposes of illustration, it will
appreciated that alternatives, modifications and equivalents may be
practiced without departing from the invention and the invention
herein is limited only by the appended claims.
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